Answer
Balanced equation:
$Cr_2O_3(s) + 3H_2(g) --\gt 2Cr(s) + 3H_2O(g)$
Reaction type: Single replacement.
Work Step by Step
$Cr_2O_3(s) + H_2(g) --\gt Cr(s) + H_2O(g)$
1. Balance the number of chromium atoms, by putting a "2" in front of $Cr$.
$Cr_2O_3(s) + H_2(g) --\gt 2Cr(s) + H_2O(g)$
2. Balance the number of oxygen atoms, by putting a "3" in front of $H_2O$.
$Cr_2O_3(s) + H_2(g) --\gt 2Cr(s) + 3H_2O(g)$
3. Balance the number of hydrogen atoms, by putting a "3" in front of $H_2$.
$Cr_2O_3(s) + 3H_2(g) --\gt 2Cr(s) + 3H_2O(g)$
4. Classify the reaction.
That reaction follows the pattern for a single replacement reaction.
$AB + C --\gt A + CB$
